RAS question
Bioaccumulation differs from biomagnification in that:
Correct answer: (D) Bioaccumulation occurs within one organism; biomagnification occurs across trophic levels in food chain.
Bioaccumulation is the build-up of a chemical within a single organism, whereas biomagnification is the increase in chemical concentration as it moves through trophic levels in a food chain.
Explanation
Bioaccumulation and biomagnification are related contaminant-transfer processes, but they operate at different scales. The EPA describes bioaccumulation as the uptake of chemicals by a plant or animal, either directly from contaminated soil, sediment or water, or by eating food that contains the chemical. In bioaccumulation, the toxin builds up in one organism faster than it can be excreted. Biomagnification, by contrast, concerns transfer through the food web: chemical levels increase from one trophic level to the next, so a predator may carry a higher concentration of a chemical than its prey. That is why option D captures the difference precisely.
Why the other options are wrong
- (A) A weather phenomenon is unrelated to either process, because both bioaccumulation and biomagnification describe chemical uptake and transfer in organisms and food chains.
- (B) A type of food is not the distinction being tested; food can be a route of chemical intake, but bioaccumulation and biomagnification are contaminant processes, not foods.
- (C) A type of mining does not explain the ecological mechanism, since the terms refer to how chemicals build up in organisms and increase through trophic levels.
Concept
This tests the Environment and Ecology concept of pollutant movement through organisms, food chains and trophic levels. It recurs in RAS because such terms are central to questions on environmental contamination, ecological risk and food-web effects.